(1) Field
The field of art to which the invention pertains is automatic power printing or typewriting apparatus having provision for recording signals on an associated record media and for printing documents automatically in response to the signals as they are read from the media. Further, the invention relates particularly to the control of paragraph indentation levels as printing on documents proceeds during the playback of information from the storage media. This involves the establishment of left margins and indentation levels that may vary from paragraph to paragraph and that are primarily established under counter control.
(2) Prior Art
The Locklar, et al, Sims, and Ross patents, as well as the Palmer and Becker patents noted in the Cross Reference section above are considered to be the most direct prior art in so far as the teaching of a printer interconnected with a tape unit for recording code signals on a tape media in response to key depressions on the printer and for subsequently reproducing the code signals and supplying them to the printer for the automatic preparation of documents. During the preparation of conventional letterhead documents or documents, such as patent specifications, a left margin is usually selected and retained throughout the preparation of an individual document. There is seldom any requirement for changing of indentation levels of individual paragraphs as printing proceeds. Under these conditions, the apparatus disclosed in the cross references noted operate in a highly capable fashion and with considerable flexibility and speed.
Under some circumstances, a variety of paragraph indentation levels are required in the same document and it is this area of document preparation with which the present invention is concerned.
A number of other references are of interest in connection with the establishment of a plurality of left margins or indentation levels during the document preparation. Counter control of document format or indentation levels has been known but, to the present time, has been manually or semiautomatically oriented. In one case, for example, a counter is used to control tabulation in a printer in opposite directions but the count level is established by means of switches that are manually manipulated. In another case, a prewired program controls the establishment of appropriate left margins during the preparation of documents. To change the indentation or format control, it is necessary to rewire the program. In still another case, a counter controls the printing of characters from a memory at specific individual horizontal printing locations but is not operable to control paragraph indentation levels. In another prior art apparatus, character signals are derived from a perforated tape that also contains special carriage return codes that are recognized and that serve to select one of a plurality of left margins. As is evident, the codes are stored in a permanent fashion and a different punched sequence of left margin format or indentation operations requires the preparation of another tape record media.
The present inventive arrangements overcome much of the inflexibility of the prior art since counter means is provided that may be set up differently as typing proceeds during the preparation of any document and, in fact, during the printing of individual paragraphs.